Vibrating screen drive



Feb. 27, 1968 P. BRUNINGHAUS VIBRATING SCREEN DRIVE 2 Sheets-SheetOriginal Filed Aug. 26, 1963 IFIG.I.

INVENTOR Pclui Briininghuus BY M 7W ATTORNEYS FIG.6.

Feb. 27, 1968 P. BRUNINGHAUS VIBRATING SCREEN DRIVE 2 Sheets-SheetOriginal Filed Aug. 26, 1963 FIG m B M m V MOTO R INVENTOR PaulBr'dninghaus BYzfizwbdm/ 767/5 FIG.|3.

ATTORNEYS United States Patent 16 Claims. or. 209 sss ABSTRACT OF THEDISCLOSURE A device for etficiently electrically driving a flexiblescreen of the type used as an industrial sieve for imparting a vibratingmotion to the same. The device consists of a number of semi-flexiblearms, fixed at one end and attached at the other directly to the edge ofthe flexible screen. Each arm is provided with an alternating currentelectromagnet, the field of which is directed to an armature attachedand located substantially midway between the two ends of the arm. Thevibrating motion imparted to the arm by the alternating magnetic fieldis amplified through the inherent flexibility of the arm itself andtransmitted to the arm-suspended screen.

This application is' a continuation of application Ser. No. 304,755,filed Aug. 26, 1963, now abandoned.

The present invention relates to a drive for a machine of the type usedfor preparing materials, as for example, machines for dewatering,concentrating, screening, classifying, and so on, materials such as ore,coal, gravel, and the like. The drive according to the present inventionincorporates means for producing pulses, e.g., an elect-rornagnetenergized by alternating current, a freely oscillating armature arrangedin the magnetic field of the magnet, and a transmission device which isstruck or moved by the armature and which acts on or is otherwiseoperatively associated with the machine.

In known drives of the above type, both sides of the armature arespring-mounted in the frame or housing of the pulse generator. If thedrives incorporate electromagnets, they utilize the alternatingfrequency of the cur-rent mains from which the electromagnet isenergized (generally 50 to 60 c.p.s.) and, in the case of a freelyoscillatable armature, produce sinusoidal oscillations of, for example,100 to 120 c.p.s. Other drives of this type are in the nature of motorsincorporating an unbalance, i.e., an eccentric mass, and still othertypes of drives used for this purpose incorporate mechanically,hydraulically or pneumatically actuated hammer-like elements. In knownelectromagnetic drives of this type, in which the amplitude of thearmature oscillations is limited, for example by means of abutments, thesinusoidal oscillations have high-frequency harmonies superimposed onthem.

If a drive of the above type, incorporating an armature which isresiliently held on both sides, is used for driving the surface of ascreening machine, the best that can generally be obtained areoscillations having an amplitude of about 1 mm. or smaller. Thisobviously limits the usefulness of the machine.

Heretofore, a substantial portion of the kinetic energy produced by thedrive and acting on the armature, was lost in the spring mounting of thearmature, so that only small amounts of energy were available tooscillate the armature.

It is, therefore, the primary object of the present invention to providea drive which overcomes the above drawbacks, and, with this object inview, the present invention resides in a drive which incorporates an armthat is 3,379,706 Patented Feb. 27, 1968 held at but one end, which armcarries an armature and is oscillatable, at its other end, in twodegrees of freedom as will be explained more particularly below. Moreparticularly, the invention resides in a drive which comprises supportmeans, arm means having two opposite ends, an armature carried by thearm means intermediate the ends thereof, an electromagnet arranged onthe support means to coact with the armature, and means for mounting butone of the ends of the arm means on the support means, thereby to leavethe other end of the arm means free to move in two degrees of freedom,the first degree of freedom being the movability of the arm means beforethe armature strikes against the electromagnet while the second degreeof freedom is the movability of the arm means after the armature abutsagainst the electromagnet. Means are further provided for connecting theother end of the arm means to a part of a machine which is to be movedor vibrated, in particular, to the naturally flexible edge of thewebbing of a screening machine, the arrangement being such that the armmeans, the armature, the connecting means and the mentioned part of themachine together form an oscillata-ble component.

Additional objects and advantages of the present invention will becomeapparent upon consideration of the following description when taken inconjunction with the accompanying drawings in which:

FIGURE 1 is a diagrammatic front elevational view of a screening machineaccording to the present invention.

FIGURE 2 is a top view of the structure shown in FIGURE 1.

FIGURE 3 is a side view of the structure of FIGURES 1 and 2.

FIGURE 4 shows the path which will be followed by the material beingscreened if the electromagnets on the sides of the webbing are energizedin a given manner.

FIGURE 5 shows the path which will be followed by the material beingscreened if the electromagnets on the sides of the webbing are energizedin a different manner.

FIGURE 6 is a sectional view, on an enlarged scale, of one embodiment ofa drive according to the present invention.

FIGURE 7 is a sectional view of another embodiment, showing the parts inanother position.

FIGURE 8 is a sectional view of still another embodiment of the presentinvention.

FIGURE 9 is a sectional view of yet another embodiment of the presentinvention.

FIGURE 10 is a sectional view of a further embodiment of the instantinvention.

FIGURE 11 is a sectional view showing the operation of a drive accordingto the present invention.

FIGURE 12 is a front view showing a disc constituting part of anelectric control device intended for use with a machine according to thepresent invention.

FIGURE 13 is a sectional view taken on line 13-13 of FIGURE 12 andincludes a circuit diagram showing the electrical connections of theelectromagnets with the control device.

Referring now to the drawings and to FIGURES 1 to 3 thereof inparticular, the same show a screening machine incorporating twolongitudinal beams l which are themselves supported by a suitable frame(not shown in FIG- URES 1 to 3), these beams constituting the solesupport means for carrying the components of the machine insofar as theyare related to the present invention. Each of the beams 1 carries threeelectromagnets 2 which are arranged so as to be inclined. Below eachelectromagnet 2 is a corresponding armature 3 connected to arms 4, oneend of each of which arms is held by a mounting device 5 which mountssuch arm on the beam 1. The other ends 7 of the arms 6 which projectfrom the other side of each armature 3 carry the fabric or other webbing8 constituting the screening surface and located between the beams 1.The webbing proper is bound at its edges by flexible stripping 9 which,as shown in the drawings, is actually held by the other ends 7, thisstripping thus serving as a movable mounting for the other ends 7. Theends 7 are suitably connected to the stripping 9, as, for example, byconnecting means such as a bolt 7a and nut 7b. The transverse ends ofthe webbing are free, so that the webbing as a whole is freely movablein a direction transverse to its length.

The beams 1 are displaceable with respect to each other, so that thehang of the webbing 8 can be adjusted as desired, this being shown bythe dashed lines.

Furthermore, the arrangement is such that both beams 1 together can beinclined at different angles, so that the webbing 8 can be given anydesired angle of inclination. The beams can also be made mutuallydisplaceable relative to each other in horizontal as well as verticaldirection.

In order to prevent the armature 3 from moving too far away from therespective electromagnets 2, the arrangement is provided with abutments10 which can also serve to support the armatures 3 in their restpositions, as well as to superimpose high frequency harmonics on thearmature oscillations.

The beams 1 also carry a receiving trough 11 into which falls thematerial which can pass through the webbing 8, as well as a receptacle12 which is arranged at the delivery end of the webbing (the left handend, as viewed in FIGURE 3) which is opposite to the receiving end (theright hand end, as viewed in FIGURE 3) at which the material to bescreened is applied onto the webbing, the receptacle 12 being at such aheight as to receive the material which does not pass through thewebbing 8. Also shown is an upper cover 13 which is likewise carried bythe beams '1, the center piece 13a of the cover being elas- FIGURE 5shows the path followed if the left side is energized with a frequency aof 50 c.p.s. and the right side from 2 to c.p.s as a stroke or impact x,with a time interval of 80 to 20.

It will be appreciated that, by varying the frequencies and timeintervals, various other paths can be obtained.

FIGURE 6 shows one embodiment of the drive per se in detail, the arms 4and 6 being rigid and connected to opposite sides of the armature 3. Theend 7 of the arm 6 which is not secured to the beam serves as the actualpulse generator. The armature 3 has an upper surface 3', which, when thecomponent incorporating the parts 4, 3, 6, is in the rest positionillustrated in FIGURE 6, is inclined with respect to the lower surface2" of the core 2' of the electromagnet 2, so that, upon maximumattraction, the armature surface 3' will be substantially parallel vtothe core surface 2". The mounting device 5 can be constituted by ahearing which allows pivotal movement of the arm 4. As shown in FIGURE6, the end of the arm means which is not secured to the beamand whichconstitutes the oscillatable component is free to move in two degrees offreedom a and b, i.e., the free arm means will have a first degree offreedom while the entire arm means, extending over length (1, moves, andits second degree of freedom after the armature 3 strikes theelectromagnet 2 and only so much of the arm as extends over the length bcan move.

FIGURE 7 shows the oscillatable component in its 'maximum attractedposition in which the upper surface 3' of the armature 3 is parallel tothe lower surface 2" of the core 2' of the electromagnet 2. In FIGURE 7,the arms 104 and 106, instead of being substantially rigid, areconstituted by leaf springs of suit-able strength, in which case theinherent elasticity of the arm 106 will, upon oscillation of thecomponent 104, 3, 106, swing between the extreme positions representedby dashed lines. The mounting device used in this embodiment isconstituted by two plates 105' whichclamp the left end of the spring arm104.

The embodiment of FIGURE 8 differs from those which are described abovein that the armature 103 has an upper surface 103 parallel with the arms104 and 106,

while the electromagnet 102 is so inclined (cf. FIGURE 1) that the lowersurface 102" of the core 102' will, upon maximum attraction of thearmature 103, be parallel with the upper surface 103 thereof.

FIGURE 9 shows an embodiment which is provided with an adjustableabutment 10, the same being threadedly mounted so that the distancebetween the upper end of the abutment 10 and the armature 3, while thelatter is in rest position, can be varied by turning the abutment 10.

The purpose of the abutment is to prevent the armature from movingbeyond the magnetic field produced by the electromagnet, as well as tosuperirnpose harmonics on the oscillation of the component 4, 3, 6. Theabutment may also serve to support the armature 3 in its rest position.FIGURE 9 also shows the mounting device 205 as being constituted .by arubber joint which clamps the left hand end of the arm 4 to allow theoscillatable component to move out of its rest position. i

The embodiment of FIGURE 10 differs from the previouly described ones inthat the two arms are constituted by a single continuous element such asa rod 46 which carries the armature 3. The mass at the free end 7represents the weight of the webbing 8 supported by the oscillatablecomponent 46, 3. 7

FIGURE 11 shows the operation of the device. The mass at the free ,end 7will lag with respect to the armature, so that the oscillations at thefree end 7 can be said to be phase-shifted with respect to theoscillations of the armature 3. FIGURE 11 also shows the abutment 10 asbeing equipped with a resilient. tip 10a.

FIGURES 12 and 13 shows a control device for use with the variable driveaccording to the present invention. The same includes a shaft 19carrying a disc 16 made of insulating material and driven by a variablespeed motor 20. The disc 16 carries concentrically arranged bridgingcontacts 17 and 17a which, depending on the desired rate of pulsegeneration, are, in circumferential direction, linear or substantiallypoint-shaped, thereby to produce either prolonged or very short instantsof energization as will be described. The contacts 17 are arranged aboutone circuit on the disc 16 while the contacts 17a are arranged aboutanother circuit of difierent (here smaller) diameter. Coact ing with thedisc 16 are two sets of brushes 18, 18', and 18a, 18a, the first setbeing arranged so as to be bridged by the contacts 17 and the second setbeing arranged so as to bebridged by the contacts 17a. The contacts 18and 18a are connected to one terminal of a suitable source 21 ofelectric power whose other terminal is grounded. The brush 18 isconnected to one terminal of each of a plurality of electromagnets 2a,the other terminals of each of which is grounded, While the brush 18a isconnected to one terminal of each of a plurality of electromagnets 2b,the other terminal of each of which is likewise grounded; Theelectromagnets 2a represent the electromagnets 2 on one side of thewebbing 8 while the electromagnets 2b represent those on the other sideof the Webbing. It will be appreciated that each electromagnet 2a willbe energized throughout time intervals whose occurrence and duration isdetermined by the position and circumferential length of the contacts17, while each electromagnet 2b will be energized throughout timeintervals whose occurrence and duration is determined by the positionand circumferential length of the contacts 17a. In the illustratedembodiment, each electromagnet 2a will, during one revolution of thedisc 16, be energized three times, while each electromagnet 2b will beenergized twice, the instant and duration of energization being, asstated above, dependent on the position and circumferential length ofthe various contacts 17, 17a. A circumferentially very short, orsubstantially point-shaped, contact will produce a single stroke It willbe seen from the above that the energization of each set ofelectromagnets can readily be preselected by providing a disc on whichthe contacts 17, 17a, are appropriately configured. If desired, it isalso possible to provide either or both of the contact rings along whichthe contacts 17, 17a, are arranged with two or more sets of brushes. If,for example, an additional set of brushes 18, 18', were provided andconnected in parallel with the set 18, 18', already shown, theelectromagnets 2a would, during each revolution of the disc 16, receive2 3=6 intervals of energization.

The following are further numerical examples of how the two rows ofdrives may be actuated:

Example 1 One row of drives is energized at a frequency of 100 c.p.s.,and the other at a frequency of 50 c.p.s., the circuit diagram of FIGURE13 then being modified so that each set of electromagnets is energizedwith a voltage of difierent frequency.

Example 2 The two rows of drives are energized alternately, as follows:

One row of drives is energized at a frequency of 100 c.p.s. for a timeinterval of $4; second, while the other row of drives is energized at afrequency of 50 c.p.s. for a time interval of second.

Example 3 The two rows of drives are energized as follows:

During a given time interval, one row of drives is energized at 50c.p.s. for 2 second, while the other row of drives is energized at 50c.p.s. for 4X i second.

Example 4 One of the two rows of drives is energized at 50 c.p.s., whilethe other row of drives is energized to produce a series of singlestrokes (cf. FIGURE 5).

It will be seen, then, that the material to be screened can be made tofollow a given path, depending on the energization of the two rows ofdrives. If a long, zigzag screening path is desired, the series ofstrokes of Example 4 will be used, because this will send the materialfrom one side of the screen to the other.

The drive means according to the present invention, in which one of theends of the arm means forming part of the oscillatable component is freeto move in two directions, produces oscillations whose amplitude issubstantially greater than those produced by comparable prior artdrives. In particular, it has been found that whereas with prior artdrives in which the ends of the arm means are not free to move in twodirections, the amplitude of oscillation is about 1 mm., the freedom ofmovement as taught by the present invention allows amplitudes of 2 mm.or higher to be reached. Consequently, the efiiciency of the machine issubstantially increased.

Another feature of the present invention is that the weight of themachine part connected to the end 7 acts as a return force which actsagainst the magnetic field produced by the electromagnets. This allowsthe armature to oscillate in synchronism with the frequency applied tothe electromagnet, so that, as stated above, the arm means, thearmature, the connecting means and the mentioned machine part togetherform an oscillatable component.

6 This feature also contributes to the fact that greater oscillationamplitudes can be obtained.

In practice, the electromagnets can be energized with alternatingcurrent via stepping transformers or half-wave rectifiers, or via aprogram control device which allows any one of a plurality of programsto be used.

According to another feature of the present invention, the drives,instead of being arranged in lines at opposite sides of a webbing, arearranged next to each other along a closed curve, e.g., -a circle abouta webbing or other part of a machine which is to be vibrated.

According to another feature, the plurality of drives which areconnected to the webbing or other machine part are subdivided into twoor more groups (e.g., one group being constituted by the drives 2a andthe other by the drives 21), as shown in FIGURE 13) which are energizedin accordance with preselected programs which are correlated to eachother, with respect to frequency, intensity, and duration of intervals,to produce a desired screening effect. In certain cases, the group ofdrives may include but one drive. In any event, the energization of thevarious drives may be so timed as to cause the part to be vibrated toundergo the desired movement.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes, andadaptations, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

What is claimed is:

1. A screening machine comprising, in combination:

(1) flexible webbing having two opposite lateral flexiole edges;

(2) a plurality of drives for shaking said webbing each one of saiddrives including (a) support means;

(b) arm means having two opposite ends;

(c) an armature carried by said arm means intermediate said endsthereof;

(d) an electromagnet arranged on said support means to coact with saidarmature;

(e) means for mounting but one of said ends of said arm means on saidsupport means, thereby to leave the other end of said arm means free tomove in two degrees of freedom; and

(f) means connecting said other end of said arm means to one of saidflexible edges of said webbing;

(g) said arm means, said armature, said connecting means and saidwebbing forming an oscillatable component;

(3) some ones of said plurality of drives arranged along one of saidlateral edges of said webbing, the respective connecting means of saiddrives connecting said one edge to the respective arms means; and

(4) the remaining ones of said plurality of drives arranged along theother of said lateral edges of said webbing, the respective connectingmeans of said drives connecting said other edge to the respective armmeans.

2. A screening machine as defined in claim 1, further comprising anabutment arranged opposite said electromagnet and positioned to beengaged either by said arm means or said armature.

3. A screening machine as defined in claim 1 wherein said arm means aresubstantially rigid, and wherein said mounting means are a means formovably mounting said one end of said arm means.

4. A screening machine as defined in claim 3 wherein said mounting meanscomprises a pivot joint.

5. A screening machine as defined in claim 3 wherein said mounting meanscomprise resilient holding means which hold said one end of said armmeans.

6. A screening machine as defined in claim 1 wherein said arm meansinclude leaf spring means extending at least between said armature andsaid one end of said arm means and wherein said mounting means fixedlyhold said One end of said arm means. 7

7. A screening machine as defined in claim 1 wherein said arm meansinclude leaf spring means extending at least between said armature andsaid other end of said arm means.

8. A screening machine as defined in claim 1 wherein said arm meansinclude two parts, one extending between said armature and said one endof said arm means and the other extending between said armature and saidother ,end of said arm means.

9. A screening machine as defined in claim 1 wherein said arm means areconstituted by a single element extending from said one end of said armmeans to said other end thereof.

10. A screening machine as defined in claim 1 wherein said electromagnetincludes a core having a surface and said armature has a surfacedirected toward said core, said surfaces being so oriented with respectto each other that, upon maximum attraction of said armature by saidelectromagnet, said surfaces are substantially parallel with each other.

11. A screening machine as defined in claim 1 wherein the support meansof all of the drives along said one side of said webbing is constitutedby a beam common to all such drives and the support means of all of thedrives along said other side of said webbing is constituted by anotherbeam common to all such last-mentioned drives.

12. A screening machine as defined in claim 11 wherein said beams areadjustable with respect to each other to permit variation of the widthand hang of said webbing.

13. A screening machine as defined in claim 11 wherein said beams aremounted on a frame to permit adjustment of the inclination of the beams.

- comprising means for energizing given groups of electro- 14. Ascreening machine as defined in claim 1, further magnets in accordancewith predetermined programs, respectively.

15. A screening machine as defined in claim 1, further comprising meansfor energizing the electromagnets of the plurality of drives arrangedalong said one side in accordance with a preselected program, and meansfor energizing the electromagnets of the plurality of drives, arrangedalong said other side in accordance with another preselected program,said programs being correlated to each other, with respect to frequency,intensity,.and duration of intervals, to produce a desired screeningeffect.

16. A screening machine as defined in claim 15 wherein said energizingmeans comprise a rotatory disc, contact means arranged about at leastone circle on said disc which is concentric with the axis of said discfor establishing an electrical connection which energizes saidelectromagnets, and a variable speed motor for driving said disc at adesired rotational speed.

References Cited UNITED STATES PATENTS HARRY B. THORNTON, PrimaryExaminer.

" R. HALPER, Assistant- Examiner.

